Heymow - Lawnmower Racing Forum

Mower Building / Setup Help => Driveline => Topic started by: crazycraftsman on March 11, 2013, 11:31:34 pm

Title: Snapped solid axle.3/4
Post by: crazycraftsman on March 11, 2013, 11:31:34 pm
My axle snapped straight in half. It was to be a high qaulity steel .Looking at the break the steel looked porous 1/2 way through then smooth but might be like that from rubbing up against each other.I took it to the steel shop and said it had nothing to do with the quilty  , must of had somthing misalined . It broke inside the frame 1 1/2 from sprocket and 1 1/2 from right side axle bearing and  on the edge of a keyway .I run a mild built 31 ohv. I've ordered a crome moly axle and a want to put a third bearing in and debaiting were to put it. I was thinking as close to sprocket as possible?????I was just breaking in motor and didn't beat on it.Nothing to be binding in trans or brakes.ROLLED SMOOTHLY WITH NO EFFORT.Should i put the third bearing beside spocket for more support or right side, outside of frame?????Has anyone had one just snap and found out why???Thanks for any input.Could of been one nasty crash.
Title: Re: Snapped solid axle.3/4
Post by: jerb on March 11, 2013, 11:46:28 pm
what class mower is this...unless its a real lightweight machine, 3/4'' is too small in my opinion!
Title: Re: Snapped solid axle.3/4
Post by: cycloneracer on March 11, 2013, 11:52:52 pm
3/4" is too small for a real racing mower.    Or any racing mower in my opinion.

Time to upgrade.

Title: Re: Snapped solid axle.3/4
Post by: crazycraftsman on March 12, 2013, 12:06:14 am
Mower is 200 pounds and i'm 160.I ran 8 race events last year with a 28 ohv and didn't have any problems and drove it like i stole it.I don't have 400 dollars to change my hole setup to 1 1/4 and club rules locally don't allow cart rims.I would understand it bending but not snaping.Thanks for the input but there's got to be a way to make this work or just had a bad axle.It's a mini craftsman.picture is posted under new mod x close to top.
Title: Re: Snapped solid axle.3/4
Post by: cycloneracer on March 12, 2013, 12:14:07 am
$400????

I just bought a 1 1/4" axle for $62.  New. Bearings for $32 each.

Was your axle cold rolled steel?   Keyed at a machine shop?    Did they case harden it?

Got a buddy that has a slow SP with 3 bearings and a 3/4" axle.   Has bent it 3 times.

Title: Re: Snapped solid axle.3/4
Post by: docbro on March 12, 2013, 12:34:35 am
Owen,

Try to use 3/4" ID tubing cut to length to act a s a spacer between components, bearings, sprocket hubs, brake hub, wheel hubs, etc.  It might help with flex issues, but won't help much with torque issues.  It will also be more time consuming to assemble.
Title: Re: Snapped solid axle.3/4
Post by: crazycraftsman on March 12, 2013, 12:35:34 am
+ rims 2,sprockets,hubs for wheels , hub for disk brake,hub for sprocket.Can't remmember what grade steel it was .special order.key ways only cut where needed.I got the 3/4 i/d pipe on the axle.thanks for the input kenny.
Title: Re: Snapped solid axle.3/4
Post by: cycloneracer on March 12, 2013, 12:44:13 am
Hardened or mild steel?   

What did all the stuff cost you the first time?   Hubs? Bearings? Locks? Collars? Sprocket hub? Brake hub? 

And the special keyed axle?

Again MY OPINION 3/4" is too small for a racing mower.
Title: Re: Snapped solid axle.3/4
Post by: Burwell555 on March 12, 2013, 12:47:46 am
$400????

I just bought a 1 1/4" axle for $62.  New. Bearings for $32 each.

Was your axle cold rolled steel?   Keyed at a machine shop?    Did they case harden it?

Got a buddy that has a slow SP with 3 bearings and a 3/4" axle.   Has bent it 3 times.



And allow me to point out that Paul bought the good bearings for that price. 95% of guys run bearings that are $6-7 each!!
Title: Re: Snapped solid axle.3/4
Post by: cycloneracer on March 12, 2013, 12:51:26 am
$6-7 bearings????    That is crazy talk!!!!!!
Title: Re: Snapped solid axle.3/4
Post by: crazycraftsman on March 12, 2013, 12:53:09 am
About 160 . I do understand 1' or 1 1/4 axle is way better and it's not really cost.Trying to find ideas why it snapped???? It was hardened.Ive heard of lots of people bending there 1' and 1 1/4 axles but snap.
Title: Re: Snapped solid axle.3/4
Post by: cycloneracer on March 12, 2013, 01:00:55 am
Hardened before or after it was keyed?


If cost wasn't an issue why bring up the $400?


Title: Re: Snapped solid axle.3/4
Post by: crazycraftsman on March 12, 2013, 01:08:16 am
Because we run lawnmowers not cart stuff.Hardened before.Maybe they sold me somthing different then they said it was.I'm no steel expert.
Title: Re: Snapped solid axle.3/4
Post by: cycloneracer on March 12, 2013, 01:11:05 am
That is why it broke. 


Need to harden after keyed. 



Make the upgrade.  You won't be sorry.    Or wasting any money. 
Title: Re: Snapped solid axle.3/4
Post by: George Herrin on March 12, 2013, 06:15:47 am
No matter how you look at it 3/4 will not last if it would more would be using it. If it dont bend it will break. Just not designed for that application.
Title: Re: Snapped solid axle.3/4
Post by: trbinrat on March 12, 2013, 06:59:39 am
We run 3/4 4140 chrome moly axle in one of our jp trans axles and we've bent it twice. A third bearing will help but eventually you will bend it. Heck last year I bent a chrome moly 1 1/4 axle.
Title: Re: Snapped solid axle.3/4
Post by: zach87cp on March 12, 2013, 09:23:05 am
Even if it was $400 that's cheap insurance if it would break at 35 or 40 and got hurt hospital bills and being off works a lot more expensive than that.
Title: Re: Snapped solid axle.3/4
Post by: Jim Knutson on March 12, 2013, 10:01:24 am
Because we run lawnmowers not cart stuff.....
Owen, you need to tell the club you run with to get real, and get safe. running all mower stuff is not safe...it's for cutting grass at 3.5mph. you already run a kart brake, and you want a chromoly axle ( never from a lawnmower), and you use billet engine parts (never from a lawnmower). its just the safe thing to do, and there is no room for argument.  :twocents:
Title: Re: Snapped solid axle.3/4
Post by: crazycraftsman on March 12, 2013, 10:28:51 am
Alright you guys convinced me .Where is the best place to order a complete package for a good price???? 4 BOLT OR 3 BOLT RIMS?1 1/4 crome holy hollow or ??? Thanks for the help and input. :)
Title: Re: Snapped solid axle.3/4
Post by: The Tank on March 12, 2013, 10:42:00 am
Looks like you run 6 inch wheels on the back. If that is correct I would order 3 bolt wheels and hubs. 1 1/4" chromoly axle that is hollow will be plenty.
Title: Re: Snapped solid axle.3/4
Post by: redline on March 12, 2013, 10:49:29 am
(http://i1233.photobucket.com/albums/ff391/redline9/oh_snap.jpg)
Title: Re: Snapped solid axle.3/4
Post by: Jim Knutson on March 12, 2013, 10:50:57 am
i would also make sure to get the 1/4" wall axle, as its easier to use a standard piece of keystock vs the thinner walled axle keys, which are not square ( they are like 3/16" x 1/4" rather than 1/4" x 1/4" because they can't cut the keyway as deep on the thinner walled axle ). BMI karts, APS karts, or EC Distributing can get all you need.
Title: Re: Snapped solid axle.3/4
Post by: Burwell555 on March 12, 2013, 11:05:06 am
$6-7 bearings????    That is crazy talk!!!!!!

I buy em for that all the time Paul! I believe Ec has a cheap bearing for $8 a piece as well. If they don't they used to!
Title: Re: Snapped solid axle.3/4
Post by: The Tank on March 12, 2013, 11:24:58 am
I buy em for that all the time Paul! I believe Ec has a cheap bearing for $8 a piece as well. If they don't they used to!
Same here. Keep them greased and I've never had one fail.
Title: Re: Snapped solid axle.3/4
Post by: Burwell555 on March 12, 2013, 11:33:56 am
Same here. Keep them greased and I've never had one fail.

Thats the key, I pull the shield out and pack em with good waterproof grease then reinstall shields. My last set has been in for two years and I have no intention of replacing them anytime soon!

I lied, EC has em for $7.50. BMI and PMI are a little higher on their website than the swap meet they come to locally every year. Online they are about $9, I bought a pair at the last swap for $12
Title: Re: Snapped solid axle.3/4
Post by: crazycraftsman on March 12, 2013, 01:17:46 pm
Thanks i,ll price out EC and BMI. I'm running 8" rear rims,but might switch back to 6".I don't know what i was thinking,guess just didn't know better.Thanks again. :)